Answer: Your answer of the question is:
The scale factor is 0.8 or your first answer
Explanation:
I know this because if you use the formula new over old or 8 over 10 in this case it is 8 is the pre-image and 10 is your image. So that is why the answer is 0.8 because its in the fraction of new over old is 8/10. I really hope I got it right and I hope you have a great weekend and a great school year. :)